/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package com.sun.org.apache.xml.internal.security;

import java.io.InputStream;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.ArrayList;
import java.util.List;

import javax.xml.XMLConstants;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import com.sun.org.apache.xml.internal.security.algorithms.JCEMapper;
import com.sun.org.apache.xml.internal.security.algorithms.SignatureAlgorithm;
import com.sun.org.apache.xml.internal.security.c14n.Canonicalizer;
import com.sun.org.apache.xml.internal.security.exceptions.XMLSecurityException;
import com.sun.org.apache.xml.internal.security.keys.keyresolver.KeyResolver;
import com.sun.org.apache.xml.internal.security.transforms.Transform;
import com.sun.org.apache.xml.internal.security.utils.ElementProxy;
import com.sun.org.apache.xml.internal.security.utils.I18n;
import com.sun.org.apache.xml.internal.security.utils.XMLUtils;
import com.sun.org.apache.xml.internal.security.utils.resolver.ResourceResolver;
import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;


/**
 * This class does the configuration of the library. This includes creating
 * the mapping of Canonicalization and Transform algorithms. Initialization is
 * done by calling {@link Init#init} which should be done in any static block
 * of the files of this library. We ensure that this call is only executed once.
 */
public class Init {

  /**
   * The namespace for CONF file
   **/
  public static final String CONF_NS = "http://www.xmlsecurity.org/NS/#configuration";

  /**
   * {@link org.apache.commons.logging} logging facility
   */
  private static java.util.logging.Logger log =
      java.util.logging.Logger.getLogger(Init.class.getName());

  /**
   * Field alreadyInitialized
   */
  private static boolean alreadyInitialized = false;

  /**
   * Method isInitialized
   *
   * @return true if the library is already initialized.
   */
  public static synchronized final boolean isInitialized() {
    return Init.alreadyInitialized;
  }

  /**
   * Method init
   */
  public static synchronized void init() {
    if (alreadyInitialized) {
      return;
    }

    InputStream is =
        AccessController.doPrivileged(
            new PrivilegedAction<InputStream>() {
              public InputStream run() {
                String cfile =
                    System.getProperty("com.sun.org.apache.xml.internal.security.resource.config");
                if (cfile == null) {
                  return null;
                }
                return getClass().getResourceAsStream(cfile);
              }
            });
    if (is == null) {
      dynamicInit();
    } else {
      fileInit(is);
    }

    alreadyInitialized = true;
  }

  /**
   * Dynamically initialise the library by registering the default algorithms/implementations
   */
  private static void dynamicInit() {
    //
    // Load the Resource Bundle - the default is the English resource bundle.
    // To load another resource bundle, call I18n.init(...) before calling this
    // method.
    //
    I18n.init("en", "US");

    if (log.isLoggable(java.util.logging.Level.FINE)) {
      log.log(java.util.logging.Level.FINE, "Registering default algorithms");
    }
    try {
      AccessController.doPrivileged(new PrivilegedExceptionAction<Void>() {
        @Override
        public Void run() throws XMLSecurityException {
          //
          // Bind the default prefixes
          //
          ElementProxy.registerDefaultPrefixes();

          //
          // Set the default Transforms
          //
          Transform.registerDefaultAlgorithms();

          //
          // Set the default signature algorithms
          //
          SignatureAlgorithm.registerDefaultAlgorithms();

          //
          // Set the default JCE algorithms
          //
          JCEMapper.registerDefaultAlgorithms();

          //
          // Set the default c14n algorithms
          //
          Canonicalizer.registerDefaultAlgorithms();

          //
          // Register the default resolvers
          //
          ResourceResolver.registerDefaultResolvers();

          //
          // Register the default key resolvers
          //
          KeyResolver.registerDefaultResolvers();

          return null;
        }
      });
    } catch (PrivilegedActionException ex) {
      XMLSecurityException xse = (XMLSecurityException) ex.getException();
      log.log(java.util.logging.Level.SEVERE, xse.getMessage(), xse);
      xse.printStackTrace();
    }
  }

  /**
   * Initialise the library from a configuration file
   */
  private static void fileInit(InputStream is) {
    try {
            /* read library configuration file */
      DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
      dbf.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, Boolean.TRUE);

      dbf.setNamespaceAware(true);
      dbf.setValidating(false);

      DocumentBuilder db = dbf.newDocumentBuilder();
      Document doc = db.parse(is);
      Node config = doc.getFirstChild();
      for (; config != null; config = config.getNextSibling()) {
        if ("Configuration".equals(config.getLocalName())) {
          break;
        }
      }
      if (config == null) {
        log.log(java.util.logging.Level.SEVERE,
            "Error in reading configuration file - Configuration element not found");
        return;
      }
      for (Node el = config.getFirstChild(); el != null; el = el.getNextSibling()) {
        if (Node.ELEMENT_NODE != el.getNodeType()) {
          continue;
        }
        String tag = el.getLocalName();
        if (tag.equals("ResourceBundles")) {
          Element resource = (Element) el;
                    /* configure internationalization */
          Attr langAttr = resource.getAttributeNode("defaultLanguageCode");
          Attr countryAttr = resource.getAttributeNode("defaultCountryCode");
          String languageCode =
              (langAttr == null) ? null : langAttr.getNodeValue();
          String countryCode =
              (countryAttr == null) ? null : countryAttr.getNodeValue();
          I18n.init(languageCode, countryCode);
        }

        if (tag.equals("CanonicalizationMethods")) {
          Element[] list =
              XMLUtils.selectNodes(el.getFirstChild(), CONF_NS, "CanonicalizationMethod");

          for (int i = 0; i < list.length; i++) {
            String uri = list[i].getAttributeNS(null, "URI");
            String javaClass =
                list[i].getAttributeNS(null, "JAVACLASS");
            try {
              Canonicalizer.register(uri, javaClass);
              if (log.isLoggable(java.util.logging.Level.FINE)) {
                log.log(java.util.logging.Level.FINE,
                    "Canonicalizer.register(" + uri + ", " + javaClass + ")");
              }
            } catch (ClassNotFoundException e) {
              Object exArgs[] = {uri, javaClass};
              log.log(java.util.logging.Level.SEVERE,
                  I18n.translate("algorithm.classDoesNotExist", exArgs));
            }
          }
        }

        if (tag.equals("TransformAlgorithms")) {
          Element[] tranElem =
              XMLUtils.selectNodes(el.getFirstChild(), CONF_NS, "TransformAlgorithm");

          for (int i = 0; i < tranElem.length; i++) {
            String uri = tranElem[i].getAttributeNS(null, "URI");
            String javaClass =
                tranElem[i].getAttributeNS(null, "JAVACLASS");
            try {
              Transform.register(uri, javaClass);
              if (log.isLoggable(java.util.logging.Level.FINE)) {
                log.log(java.util.logging.Level.FINE,
                    "Transform.register(" + uri + ", " + javaClass + ")");
              }
            } catch (ClassNotFoundException e) {
              Object exArgs[] = {uri, javaClass};

              log.log(java.util.logging.Level.SEVERE,
                  I18n.translate("algorithm.classDoesNotExist", exArgs));
            } catch (NoClassDefFoundError ex) {
              log.log(java.util.logging.Level.WARNING,
                  "Not able to found dependencies for algorithm, I'll keep working.");
            }
          }
        }

        if ("JCEAlgorithmMappings".equals(tag)) {
          Node algorithmsNode = ((Element) el).getElementsByTagName("Algorithms").item(0);
          if (algorithmsNode != null) {
            Element[] algorithms =
                XMLUtils.selectNodes(algorithmsNode.getFirstChild(), CONF_NS, "Algorithm");
            for (int i = 0; i < algorithms.length; i++) {
              Element element = algorithms[i];
              String id = element.getAttribute("URI");
              JCEMapper.register(id, new JCEMapper.Algorithm(element));
            }
          }
        }

        if (tag.equals("SignatureAlgorithms")) {
          Element[] sigElems =
              XMLUtils.selectNodes(el.getFirstChild(), CONF_NS, "SignatureAlgorithm");

          for (int i = 0; i < sigElems.length; i++) {
            String uri = sigElems[i].getAttributeNS(null, "URI");
            String javaClass =
                sigElems[i].getAttributeNS(null, "JAVACLASS");

            /** $todo$ handle registering */

            try {
              SignatureAlgorithm.register(uri, javaClass);
              if (log.isLoggable(java.util.logging.Level.FINE)) {
                log.log(java.util.logging.Level.FINE, "SignatureAlgorithm.register(" + uri + ", "
                    + javaClass + ")");
              }
            } catch (ClassNotFoundException e) {
              Object exArgs[] = {uri, javaClass};

              log.log(java.util.logging.Level.SEVERE,
                  I18n.translate("algorithm.classDoesNotExist", exArgs));
            }
          }
        }

        if (tag.equals("ResourceResolvers")) {
          Element[] resolverElem =
              XMLUtils.selectNodes(el.getFirstChild(), CONF_NS, "Resolver");

          for (int i = 0; i < resolverElem.length; i++) {
            String javaClass =
                resolverElem[i].getAttributeNS(null, "JAVACLASS");
            String description =
                resolverElem[i].getAttributeNS(null, "DESCRIPTION");

            if ((description != null) && (description.length() > 0)) {
              if (log.isLoggable(java.util.logging.Level.FINE)) {
                log.log(java.util.logging.Level.FINE, "Register Resolver: " + javaClass + ": "
                    + description);
              }
            } else {
              if (log.isLoggable(java.util.logging.Level.FINE)) {
                log.log(java.util.logging.Level.FINE, "Register Resolver: " + javaClass
                    + ": For unknown purposes");
              }
            }
            try {
              ResourceResolver.register(javaClass);
            } catch (Throwable e) {
              log.log(java.util.logging.Level.WARNING,
                  "Cannot register:" + javaClass
                      + " perhaps some needed jars are not installed",
                  e
              );
            }
          }
        }

        if (tag.equals("KeyResolver")) {
          Element[] resolverElem =
              XMLUtils.selectNodes(el.getFirstChild(), CONF_NS, "Resolver");
          List<String> classNames = new ArrayList<String>(resolverElem.length);
          for (int i = 0; i < resolverElem.length; i++) {
            String javaClass =
                resolverElem[i].getAttributeNS(null, "JAVACLASS");
            String description =
                resolverElem[i].getAttributeNS(null, "DESCRIPTION");

            if ((description != null) && (description.length() > 0)) {
              if (log.isLoggable(java.util.logging.Level.FINE)) {
                log.log(java.util.logging.Level.FINE, "Register Resolver: " + javaClass + ": "
                    + description);
              }
            } else {
              if (log.isLoggable(java.util.logging.Level.FINE)) {
                log.log(java.util.logging.Level.FINE, "Register Resolver: " + javaClass
                    + ": For unknown purposes");
              }
            }
            classNames.add(javaClass);
          }
          KeyResolver.registerClassNames(classNames);
        }

        if (tag.equals("PrefixMappings")) {
          if (log.isLoggable(java.util.logging.Level.FINE)) {
            log.log(java.util.logging.Level.FINE, "Now I try to bind prefixes:");
          }

          Element[] nl =
              XMLUtils.selectNodes(el.getFirstChild(), CONF_NS, "PrefixMapping");

          for (int i = 0; i < nl.length; i++) {
            String namespace = nl[i].getAttributeNS(null, "namespace");
            String prefix = nl[i].getAttributeNS(null, "prefix");
            if (log.isLoggable(java.util.logging.Level.FINE)) {
              log.log(java.util.logging.Level.FINE,
                  "Now I try to bind " + prefix + " to " + namespace);
            }
            ElementProxy.setDefaultPrefix(namespace, prefix);
          }
        }
      }
    } catch (Exception e) {
      log.log(java.util.logging.Level.SEVERE, "Bad: ", e);
      e.printStackTrace();
    }
  }

}

